Preparation and Characterization of ZnO Nanoparticles via Thermal Decomposition from Zinc(II) Schiff Base Complex as New Precursor

Abstract

In this paper,nano-sized of mononuclear tetrahedral zinc(II) complex with the general formula of Zn((pma-ba)₂en)Br₂.2H₂O, (pma-ba)₂en=<em>N,N</em><em>¢</em>-bis{(paramethylamino)benzylidene}ethylenediamine, was synthesized by ultrasonic bath assisted from the reaction of ZnBr₂ and Schiff base ligand (pma-ba)₂en in molar ratio 1:1 in methanol solution. The zinc(II) Schiff base complex characterized by elemental analyses (CHN), Fourier transformed infra-red (FT-IR) spectroscopy, X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Also, thermal stability of the complex was studied from room temperature to 780 °C under argon atmosphere. TGA shows three stages for decomposition of the zinc(II) complex. At the end of decomposition, the remainder part is ZnO. The preparation of ZnO at the end of thermal decomposition confirmed with XRD. The XRD pattern of complex has shown that the sharp crystalline peaks indicating the crystalline phase in complex. By Scherrer's formula, the average size of the nano-sizes of the complex was calculated >200 nm, that confirmed by SEM image. In addition, ZnO nanoparticles were obtained by thermal decomposition of zinc(II) Schiff base complex at 550 °C for 3 h. XRD result that the good crystallinity for zinc(II) oxide with no impurity observed in the ZnO product. The average size of the nanoparticles of the ZnO was calculated <50 nm.